Load hoist and grappling control



Nov. 12, 1946. H, N, DMCK 2,410,965

LOAD HOIST AND GRAPPLING CONTROL Filed Nov. 16, 1943. 5 Sheetsheet 1 2e 21 r 56 141 e NOV. 12, 1946. M c 2,410,965

LOAD HOIS'I' AND GRAPPLING CONTROL Filed Nov. 16, 1943 5 Shets-Sheet 2 Nov. 12, 1946. N, DMCK 2,410,965,

LOAD HOIST AND GRAPPLING CONTROL Filed Nov. 16, 1943 5 Sheets-Sheet 3 4 9 uvz/avru nanny NOEL D M CR LOAD HOIST AND GRAPPLING CONTROL Fi led Nov. 16, 1943 5 Sheets-Sheet 4 6! Fig. 9.

121 E 125 3s v 5 3e /N/EN7"U HENRY NOEL pm K Nov. 12, 1946. H. N. DIMICK LOAD HOIST AND GRAPPLING CONTROL Filed Nov. 16, 1943 5 Sheets-Sheet 5 INL/EN 717R I v-TU NEV Patented Nov. 12, 1946 LOAD nors'r AND GRAPPLING CONTROL Henry N. Dimick, Portland, reg., assignor to Willamette Hyster Company, Portland, 0reg., a corporation of Oregon Application November 16, 1943, Serial No. 510,571

9 Claims. (Cl. 214-65) This invention relates to that class of automotive vehicles known as straddle trucks, used primarily for the transportation of loads such as stacks of lumber, boxed or crated shipments and the like, which are carried beneath the frame of the truck and between the wheels in straddled position. More particularly, the invention relates to a new and novel arrangement of elements for controlling operation of the load grappling equipment.

Straddle truck are designed to overrun a load, pick it up and carry it beneath the frame of the truck and between the wheels in straddled position. Each truck is provided with grappling means called shoes for engaging and carrying the load. In the instant invention the shoes are mounted upon swing posts mounted at each side of the truck midway between the front and rear wheels. The upper ends of the swing posts are interconnected by a rod which, though being extensible for purposes of initial adjustment, provides fixed points about which the posts swing to move the shoes between load engaging and disengaging positions. Each of the swing posts is provided with trunnions journaled in a slide mounted for limited movement transversely of the truck frame, and means is provided for imparting movement to each of these slides simultaneously in response to a control mechanism actuated by means of an operating lever in the operators compartment.

A load hoisting mechanism is provided comprising lift chains trained over drive sprockets which are operatively connected by suitable shafts and gearing to a friction drive mechanism through which power is transmited from a prime mover. The friction drive is actuated by means of vacuum power devices under control of valve mechanism operated by a lever interconnected with the aforementioned operating lever in the operators compartment. By reason of this construction, control of all of the various functions of the hoisting mechanism is had through the manipulation of but one lever mechanism.

It is, therefore, an object of the invention to provide in a straddle truck power devices for controlling the operation of the load grappling and hoisting mechanism, which power devices are actuated by an easily manipulated, manually controlled lever arrangement requiring a minimum of eifort and attention on the part of the operator.

It is a further object of the invention to provide a new and novel arrangement of power devices for controlling the operation of work performing mechanisms, together with a simple arrangement of both manually and automatically controlled actuating means for energizing said power devices.

It is a further object of the invention to provide an improved mechanism for moving the load engaging shoes on a straddle truck relative to a load to be carried, for operating the hoisting mechanism to raise or lower the load, and for applying braking means to hold said hoisting mechanism in any desired position within the limits of the hoist travel, the several functions of which mechanism are under control of a single control lever element.

It is a further object of the invention to provide in a straddle truck an improved mechanism for moving the load grappling shoes into and out of load engaging position.

It is a further object of the invention to provide an improved mechanism on straddle trucks for controlling the operation of a friction drive between the prime mover and the lifting mechanism.

It is a further object of the invention to provide in a straddle truck means for increasing the usefulness of the truck and to provide a truck capable of efiicient operation even in the hands of unskilled operators.

In the drawings: Figure 1 is a top plan view of a straddle truck embodying the invention; Figure 2 is a side elevation of the straddle truck shown in Figure 1; Figure 3 is a sectional elevation taken transversely of the truck on the line 3-3 of Figure 1, showing the construction of the means for supporting the load; Figure 4 is a plan view, partly in section, of the means for moving the load supporting elements into and out of engagement with a load, taken on the line 44 of Figure 3; Figure 5 is a'fragmentary sectional view, taken on the line 55 of Figure 3; Figure 6 is a top plan view, partly in section, of the friction drive for operating the lift chains; Figure 7 is a section taken on the line 'l---! of Figure 6; Figure 8 is a longitudinal sectional elevation of the friction drive, taken on the line 8-8 of Figure 6; Figure 9 is a sectional elevation taken transversely of the straddle truck on the line 99 of Figure 8; Figure 10 is a diagrammatic representation of the control elements for the friction drive; Figure 11 is a longitudinal elevation taken on the line |-I l of Figure 1 and showing the construction of the mechanism for raising and lowering the load; Figure 12 is a sectional elevation taken on the line l2|2 of Figure 11; and Figure 13 shows a section taken on the line |3l 3 of Figure 12.

Referring to Figure 2 of the drawings, there is illustrated a straddle truck comprising a main frame l0 mounted upon wheels it carried in wheel forks I2. Each frame member is rectangular in cross section, having spaced vertical walls l3 and M. The stems l5 of the wheel forks extend vertically above the wheels and support the frame ill at a height to permit the truck to overrun a load to be carried thereby and pick it up and carry it in a straddled position.

Power to operate the straddle truck is provided by a motor 16 from which power is transmitted by way of drive shaft l1 and differential gearing Is to the drive axles l8. Sprockets 2| are mounted on the outer ends of the drive axles l9, and trained over the sprockets 2| and over wheel sprockets 22 are drive chains 23 by means of which power is transmitted to drive the wheels The steering mechanism comprises the steering wheel 24, drag links (not shown) and tie rods 25 interconnecting steering arm 28. As is usual in trucks of this type, all of the operating mechanism, comprising both driving and hoisting mechanisms, is mounted above the frame ID to provide a load space heneath the frame and between the wheels.

As best shown in Figures 2 and 3, the load grappling equipment comprises load engaging shoes 21 adapted to be moved vertically on swing posts 28 mounted in the frame l midway between the front and rear wheels on each respective side of the truck. Brace rods 28 extendbetween the frame Ill and the lower ends of the swing posts 28 to add rigidity to the structure. The brace rods 28 are fulcrumed at their connection to the frame III to permit them to swing with the swing posts 28.

As best seen in Figure 2, the shoes 21 extend longitudinally of the truck and are supported at their ends by links 12 directly connected to the lift mechanism. Each shoe 21 is provided with parallel vertical flanges 3 extending outwardly from the vertical flange of the shoe, the two flanges 8, 9 defining a guideway for the swing post 28. Rollers 8 joumaled in the flanges 3, 8 have rolling engagement with the swing posts 28 for guiding the shoe during movement of the hoist. Each shoe is provided at its ends with horizontal flanges 1, each flange being perforated for receiving therethrough the shank of a bolt 8 which supports the shoes on the lower ends of the links 12. Each link 12 carries at its lower end a nut for receiving the threaded end of the bolt 8. The shoes 21 are mounted loosely on the bolt 8, the latter being of sufllcient length to permit vertical movement of the shoe on the shank of the bolt in the event the shoe should strike an obstruction during lowering movement of the hoist mechanism. The shoes are rotatable about the swing posts 28 in a horizontal plane,

the loose connection between the ends of the shoes and the links 12 permitting the shoes to align themselves with a load which may be angularly and laterally misplaced relative to the center line of the straddle truck.

Each swing post 28 is provided with trunnions 3| journaled in bearings 32 mounted on a slide 33 slidably mounted on a supporting structure extending between and secured to the spaced wall portions l3 and H of the frame l8. The structure may comprise members 34 supported upon angle members 35 fastened to facing surfaces of the frame walls. Both the members 34 and slides 33 are provided with openings for receiving the swing posts 28 therethrough. The slides 33 are movable transversely of the frame l8 in grooved guides 38 bolted to the supporting structure. A shaft 31 having crank arms 38 is joumaled in bearings 33 mounted on each of the supporting structures. Links 4| connect the crank arms 38 with bosses 42 on the opposite edge of each slide 33, to which the end of each link 4| is pivotally attached as by pins 43. The slides 33 are controlled by a mechanism comprising a shaft 44 extending transversely of the truck and joumaled vin bearings 45 suitably mounted on the outer walls l3 of the frame l8. Links 48 connect levers 41 mounted on the shaft 44 with levers 48 mounted on the shafts 31 whereby rotation of shaft 44 imparts simultaneous rotary movement to each shaft 31. Rotation of the shafts 31 in one direction tends to straighten the joint between'the crank arms 38 and the links 4| and moves the slides 33 transversely of the frame l8 to their innermost positions. This movement of the slides 33 swings the lower ends of the swing posts 28 inwardly of the straddle truck and moves the load engaging shoes 21 into position to pick up the load, as shown by broken lines in Figure 3., Rotation of the shaft 31 in the opposite direction causes the links 4| and crank arms 38 to move to collapsed position, whereupon slides ,83 are moved outwardly of the frame II to cause .the swing posts 28 to swing outwardly to the positions shown in full lines in Figure 3.

At their upper ends the swing posts 28 are interconnected by a rod comprising at each end thereof a link 5| connected to the upper end of the swing post by means of a pin 52. The links 5| are of insufficient length to meet in end to end abutting relation transversely of the truck. and to complete the connection between the upper ends of swing posts 23 a rod 53 is provided having threaded ends 54 received within nuts 88 carried on the free ends of the links 5|. Adjustment of the nuts 55 relative to the rod 53 de- 'termines the distance between the load engaging shoes 21 prior to manipulation of the slides 33 for moving the shoes into and out of load engag ing position.

For moving the load engaging shoes 21 vertically of the swing posts 28, as for clamping a load between the shoes and the under side of the frame l8, there is provided a hoisting mechanism comprising lift chains 58, the arrangement of which may better be understood by reference to Figures 11, 12 and 13. The lift chains shown are of multiple width, each'chain being trained over pairs of sprockets 51 mounted on drive shafts 58 and over idler sprockets 53 mounted on stub shafts 8|. The stub shafts 8| for the idler sprockets 53 are carried by standards 82 mounted adjacent the lower end of a frame 83 providing therewithin a grooved track 84 for a cross head 85. The tracks 84 are arranged vertically of the frame 83, and the cross heads are moved vertically relative to the frame in response to operation of the chains. Each cross head 88 is .provided adjacent its upper end with a socket 88 for receiving the head of a pin 81 secured to one end of each of the lift chains 58. The socket 88 provides with the pin 81 a swivel coupling between the chain 58 and the cross head 88. The

socket 88 is flared upwardly to permit the pin 81 to align itself with the chain 58 to insure that the pull will be distributed equally throughout the cross sectional. area of the, chain. From thence each lift chain 58 is trained over drive sprocket 51 and idler sprocket 58 and is connected to the cross head 85 at a 'point adjacent the connection for the pin 81. At its lower end the cross head 88 is provided with parallel flanges 83 having aligned apertures 83 for receiving therethrough a pin 1|. The link 12 is joumaled on the pin 1| and extends between the cross head 85 and the load engaging shoe 21, being secured to the latter by means of the bolt 8 and nut 5 hereinbefore described.

Friction drive for hoisting mechanism At the forward end of the motor l8 the drive shaft l1 is connected by means of a flexible coupling 14 to a shaft section 15 which in turn is connected through a flexible coupling 16 to a shaft section TI journaled in bearings 18 carried in a housing I9. The forward end of the shaft section 11 is provided with a friction cone 88 arranged between the inner sides of a friction transmission wheel 8| formed of two frusto-cones connected together at their smaller ends and forming a V-shaped annular groove 82 therebetween. The friction wheel 8I is keyed to a shaft 83 journaled in bearing 84 and 85 and connected at each end through flexible couplings 86 with shaft sections 81. The shaft sections 81 are in turn connected through flexible couplings 88 to shaft sections 89 provided with worm gears (not shown) which mesh with gears 9| keyed to the ends of shafts 58. The shafts 58 extend longitudinally of the truck, being journaled in bearings 92 mounted on frame members I8. Mounted on the shafts 58 are the pairs of sprockets 51 over which are trained the lift chains 56 hereinbefore described.

The housing I9 is of generally cylindrical shape and is rotatably supported in a block 93 slidably mounted on a grooved plate 95 fastened to the frame member 94. The position of the block 93 is adjustable in a direction longitudinally of the shaft I1 to provide for movement of the friction cone 88 toward or away from the friction wheel 8|, both for purposes of initial adjustment of these parts and to compensate for wear. Slots I 8I in the frame member 94 extend in a direction parallel to the shaft IT for receiving therethrough bolts I85 which engage in tapped recesses in the block 93. The heads of the bolts I 85 engage under a strip Washer I82 against which look washers are seated. An adjusting screw I83 equipped with a lock nut I84 forms with a boss I86 a stop against which the block 93 bears when the friction done 88 is moved into engagement with the friction wheel 8I. The block 93 is provided with spaced clamps 96 which engage around opposite end portions 9'! of the housing 19. Between the clamps 98 the housing I9 is provided with an upstanding lever arm 98. The lower surface of the housing 19 is provided with outwardly projecting cam surfaces 99 defining a recess I88 therebetween.

Bearings 78 carried within the housing I9 for supporting the shaft I1 are mounted eccentrically of the housing so that rotation of the housing operates to move the shaft TI laterally of the housing 19 and the friction cone 88 into engagement with one or the other of the frusto cones comprising the friction wheel 8| according to in which direction the housing isrotated. For imparting rotary movement to the housing 19 there is provided a pair of oppositely disposed vacuum power devices I8I and I82 bolted to upstanding flanges I83 on the frame member 94. Each of these devices comprises a casing I84 containing a flexible diaphragm I85 secured between the two halves of the casing and dividing the casing on a medial line to form two chambers. One of these chambers I 86 is open to atmosphere through an orifice I 81, whereas the other chamber I88 is closed except for a pipe connection I89 and pipe line III which connects the chamber I 88 with a control valve I I2, presently to be described. Connecting the diaphragm I85 of each power device I is a rod II3, the two rods H3, H3 extending transversely of the housing I9 and being each connected to the lever arm 98 and to each other by a pin II4. A compression spring II5, disposed in the chamber I88 between the diaphragm I85 and the end wall II6 of the casing I84, tends v Each standard I" formsa fulcrum for a lever H8, the opposite end II 9 of which bears against a boss I28 on the housing 79. A resilient compresslon element, such as a helical spring I2I, is arranged between the frame member 94 and the lever II8 for urging the lever upwardly in opposition to the turning moment of the housing 19 as created either by the oppositely disposed lever H8 or by operation of one or the other of the vacuum power devices IM and I82. For limiting the upward movement of each lever I I8 there is provided a loose connection between each of the levers H8 and the frame member 94 formed, in this instance; by a rod I22 pivotally connected at its upper end to the lever II8 by means of a pin I23 and bearing on its lower end a nut I24. The rod I22 extends through an aperture I25 in the frame member 94 and is freely slidable therein, the nut I24 engaging the under surface of the frame member 94 for limiting upward movement of the lever.

With the lever arm 98 in neutral position the friction cone 88 is held out of engagement with either side of the friction wheel BI and the load raising and lowering means are held stationary. When, however, the lever arm 98 is moved in one direction or the other, the friction cone 88 engages one side or the other of the friction wheel 8| and rotation of the drive shaft I1 is transmitted therethrough to drive the shaft 58 and actuate the lift chains 56. The direction of operation of the lift chains 56 is determined by the direction of rotation of the friction wheel 8|. Assuming rotation of the drive shaft I! in the direction indicated by the arrow I26 in Figure 6, movement of the lever arm 98 to the right will cause rotation of the friction wheel in the clockwise direction, whereas movement of the lever arm 98 to the left will cause rotation of the friction wheel in the counterclockwise direction. In one direction of rotation of the friction wheel the lift chains 56 are actuated to raise the load engaging shoes, while rotation of the friction wheel in the opposite direction operates to lower the load engaging shoes. 1 1-1,

A cam roller I21 mounted on the upper'end of an arm I28 engages in the recess I 88 between the cam surfaces 99 during the times that the lever arm 98 and shaft 11 are in neutral position. The arm I28 and cam roller I21 are part of a. brake mechanism comprising a lever I29 fulcrumed on the end of a bolt I3I and extending longitudinally beneath the friction wheel M. The bolt I3 I depends somewhat below the frame member 94, a compression spring I32 being positioned between the frame member 94 and the end of the lever I 29 to give resiliency to the brake mechanism.

The lever I29 extends to a point beneath the housing I9 where its free end is supported by a compression spring I33 mounted on a bolt I34. The spring I33 bears at one end against a nut I35 threaded on the bolt and at the other end against the under side of the lever I 29, and urges the lever I 29 upwardly in opposition to the downward thrust on the cam roller I21. A brake shoe I36, V-shaped in cross section, is mounted on the lever I29 in position to be held thereby against the inner faces of the friction wheel 8| at such times astheshaft11isinneutralposition andthecam .roller I21 engages in the recess I55. when, however, the lever arm 55 is moved either to the left Control mechanism The control mechanism for operating the load enlaging shoes 21 and the lift chains 55 may include the engine manifold I 51, a vacuum pump or any suitable means for producing vacuum. A conduit I55 connects the manifold I51 with a check valve I55, and a conduit I4I connects the check valve with a vacuum reservoir I42. A conduit I45 provides communication between the vacuum reservoir I42 and the control valve I44. Conduit I4I connects ahead of the check valve I55 with conduit I45, providing communication between the vacuum reservoir I42 and control valve 1 l2.

It will be remembered that the swing posts 25 are journaled in bearings 52 mounted on slides 55 adapted for limited movement transversely of the frame I5 through operation of toggle links 55-4I' whichin turn are controlled by rotation of the shaft 44. Rotation of shaft 44 is controlled by a servo-motor comprising a cylinder I45 within which is mounted a piston having a piston rod I41 connected by suitable coupling means to a lever I45 fastened to the shaft 44. The cylinder I45 is connected with the vacuum reservoir I42 by way of the conduits I45 and I5 I control valve I44. and conduit I45. The valve I44 may be of any 8 swingposts 'and load'cnafld l shoeiflinto or out of engagement with a load. Amuming that movement of the operatingjever I52 to the rightoperates'romovetheloadm lfl llhoel into engagement with the load. then movemmt of the operating lever I52 in the opposite direction,ortotheleft.actuatesthevalve I44tocloee the aforementioned end of the cylinder I45 to atmosphere and provide betwem said end and the vacuum reservoir I42. and to close the conduit between the vacuum reservoir andtheoppositeendofthecylinderandopen saidoppositeendtoatmosphere. Bythismeans shafts44and51 arerotatedinthcowolitedirection from that hereinbefore described. and swing posts a and load enga in shoes 2! are moved out of engagement with the load.

The operating lever I52 is also adapted for movement both in a forward direction and in a rearward direction from the neutral position. Movement of the lever in one of these directions.

for example. forwardly of the truck, actuates the valvelllsoastoplacethechamber lllofthe vacuum power device I52 in communication with suitable type well known in the art, and may be connected through suitable linkage to an operating lever I52 mounted in the operator's compartment. By control'of the valve I44 either of the opposite ends of the cylinder I may be placed in communicationwith the vacuum reservoir I42 while the other end of the cylinder is opened to atmosphere. The valve I44 is connected to the operating lever I52 by way of a link I connected to the valve I44 and a link I54 connected to the operating lever I52, the two links being interconnected by means of a cross lever I55.

It will be noted that the operating lever I52 is fulcrumed intermediate its ends on the upstanding arm I55 of the lever I51, having a tubular portion I55 Journaled in bearings I55 secured to a plate I5I comprising a part of the frame of the vehicle. The lever I51 is connected through suitable linkage I52 to the control valve 2 which controls the action of the vacuum power devices IOI and I02.

The operating lever I52 may be moved to the left and to the right, pivoting during such movements on the pin I55 mounted in the arm I55 of the lever I51. Movement of the operating lever I52 In the right actuates the valve I44 to open one end of the cylinder I45 to atmosphere and place the opposite end of the cylinder I45 in communication with the vacuum reservoir I42. Thus the piston and piston rod I41 are moved in a predetermined direction to rotate the shafts 44 and 51 to shift the slides 55 for moving the the vacuum reservoir I42, at the same time opening the chamber I55 in vacuum power device "I to atmosphere. Operation of the valve in this manner will cause the diaphragm I55 in vacuum power device I52 to move toward the endwall II5 against the resistance offered by spring 3 I5. Thus the housing 15 is rotated in the direction of the vacuum power device I52 and moves the friction cone 50 into engagement with the frusto cone on the right hand side of the friction wheel 2I. At the same time, the cam roller I21 engages the cam surface 55 to depress the lever arm I25 against the action of the spring I22 and move the brake shoe I55 out of engagement with the friction wheel 5|. Rotation of the drive shaft I1 being imparted to the shafts 51, and from thence through gears 55-5I to the shafts 55, the sprockets 51 are rotated in a predetermined direction to cause the lift chains 55 to raise or lower the cross head 55 to which shoes 21 are attached by means of the link 12. Assuming that movement of the operating lever I52 forwardly of the truck operates through the mechanism Just described to raise the load engaging shoes 21, the movement of the operating lever I52 in the opposite direction, or rearwardly of the truck, actuates the control valve I I2 to open the chamber I55 in vacuum power device I02 to atmosphere and to place chamber I05 in vacuum power device III in communication with vacuum reservoir 142, whereupon the friction cone 55 is moved into engagement with the left hand side of the friction wheel 5| and the cross shaft 51 is rotated in the opposite direction to lower the shoes 21.

Means is provided to arrest movement of the cross heads 55 whenever the cross heads approach the limits of their movements in the grooved tracks 54. It will be remembered that operation of the lift chains 55 is controlled by a friction drive which is actuated by vacuum power devices IIII and I02, and that in turn the operation of these vacuum power devices is controlled by a valve H2. The valve is actuated by a lever I51 connected to the valve by means of linkage I52. Fastened on the link I52 in spaced apart relation; are collars I54 and I55. Extending between the collars I54 and I55 is one arm I55 of a bell crank I51 iournaled on an upstanding pin I15 fastenedin the deck of the truck frame. The other arm I55 01' the bell crank I51 is connected by alink I55 tothearm I1I ofabeilcrank I12 journaled on the frame I0. A link I13 extends through the deck of the truck and is positioned adjacent the grooved track 64 in the frame 53. Fastened to the link I13 a short distance beneath the deck of the truck is a collar I14 having a stop member I15 extending into the path of movement of the cross head 65. Fastened to the lower end of the link I13 is a second collar I16 equipped with a stop member I11 likewise extending into the path of movement of the cross head 15. A pin I18 projecting horizontally from the cross head 65 is so arranged as to strikc the stop member I15 'as the cross head approaches its upper limit of movement and to strike the stop member I11 as the cross head approaches its lower limit of movement. In either instance movement of the link I13 in the vertical direction is transmitted through hell crank I12 and link I69 to hell crank I61 which in .turn moves the link I62 in the direction necessary to restore the valve I I2 to neutral position. In the neutral position of the valve II2 chambers I08 in vacuum power devices IM and I02 are subjected to equal vacuum by way of the connection with the vacuum reservoir through the valve I I2, and the lever 98 returned to neutral position. At the same time the brake shoe I36 is moved into engagement with the friction wheel 8| to stop movement of the load raising and lowering means as hereinbefore described.

Operation In operation of a straddle truck embodying the construction hereinabove described, as the truck is driven over .a load to be carried theoperator manipulates the operating lever I52 to lower the load engaging shoes 21 as the truck approaches the load. Thereupon, the lever I52 is moved to the right to cause the load engaging shoes to move into engagement with the load, whereupon the lever I51 is rotated in the forward direction to cause the valve I I2 to maintain the chamber I08 in vacuum power device I02 in communication with vacuum reservoir I42, at the same time opening the chamber I08 in vacuum power device IN .to atmosphere. Thus the friction cone 80 is moved into contact with the side of the friction wheel 8| which transmits the driving motion of the shaft I1 to the transverse shaft 81 to raise the load carrying shoes 21 and lift the load.

Upward movement of the load carrying shoes may continue until the load of lumber is clamped between the shoes and the under side of the frame I0, or movement of the load may be arrested at any desired position. When the load has been raised the operator moves the lever I51 to neutral position, thus actuating the valve II2 to cause chambers I08 in vacuum power devices HM and I02 to be subjected to equal vacuum and so restore the lever 98 to neutral position. At the same time the brake shoe I36 is moved upwardly by force of the spring I33 into engagement with the friction wheel 8| and holds the load in the raised position. An advantage of the construction resides in the fact that the friction transmission for the hoisting mechanism permits a certain amount of slippage of the transmission elements, so that the load carried by the shoes 21 may be clamped tightly against the under side of the frame I without the necessity of exactly timing movement of the lever I51 by the operator. In other words, the friction drive acts as a slip clutch between the drive shaft I1 and the cross shafts 81, and eliminates distortion or breakage of the lifting mechanism which might otherwise result from badly timed manip- 'ulationofthe operating leverif a gear transmission were used.

When the lift truck has transported the load to-the place of unloading, the'operator stops the carrier and moves the lever |.51 in the required direction to move the elements of the valve I I2 into position to actuate the transmission to drive the load carrying shoes downward. As the shoes 21 approach the-lowermost limit of their movement, the pin I18; on the cross head 55 strikes the stop member I11 on the link I13 and actuates the bell crank I61 and link I62 to move the valve I I2 to neutral position and so stop the downward movement of the load engaging shoes. Thereupon the operating lever I52 may be moved to the left to actuate the valve I and so cause the swing posts 28 to move to their outermost position for releasing the load.

Having now described my invention and in what manner the same may be. used, what I claim as new and desire to protect by Letters Patent is:

1. In a straddle truck, a frame, a pair of grappling members mounted one on each side of said truck and movable inwardly into position to engage a load, toggle levers reacting between said frame and said grappling members in a manner to vary the lateral spacing of said grappling members, means for controlling the action of said toggle levers; a transmission mechanism for transmitting power for raising and lowering a load carried by said grappling members comprising a friction cone, a friction wheel engageable by said friction cone for being driven in either of opposite directions of rotation, mea s for moving said friction cone into engagement with said friction wheel, means for controlling the direction of movement of said last named means for determining the direction of rotation of said wheel; a lever mounted on said straddle truck, means interconnecting said lever and the means controlling said grappling members, and means for interconnecting said lever and the means for controlling movement of said friction cone. said lever being movable in one direction t actuate said grappling means and being movable in another direction to actuate said friction cone moving means.

2. In a straddle truck, a plurality of control mechanisms for controlling operation of the load carrying apparatus, a lever mounted on said truck comprising a member journaled for rotation in a direction longitudinally of said truck, an upstanding arm on said member, an arm pivoted intermediate its end on said first named arm for rotation about said pivot in a direction transversely of said truck, means connecting one end of said pivoted arm with one of said control mechanisms, and means connecting said member with another of said control mechanisms whereby movement of said arm in one direction rotates said member and actuates one control mechanism and movement of said arm in a direction at right angles to said first movement actuates the other of said control mechanisms.

3. In a straddle truck, a pair of grappling members mounted one on each side of said truck and movable inwardly into position to engage a load, power means comprising a prime mover for operating said grappling members, a load hoisting mechanism connected to said grappling members for raising and lowering a load carried thereby, power means comprising a prime mover for operating said hoisting mechanism, and a single control lever means connected with each said power means, and operable to actuate either one straddle truck, means or both of said power means according to the direction of movement of said lever.

4. In a straddle truck, a pair of grappling members mounted one oneach side of said truck and movable inwardly into position to engage a load,'.

means for operating said grappling memsaid hoisting mechanism, said power means com- 1 load hoisting mechanism connected to said.

prising a frame, an eccentric iournaled in said I frame. ashaft iournaledin said eccentric, means eccentric comprising a pair of for rotating said I means connecting each of vacuum power devi said vacuum power devices with said eccentric,

means for actuating a selected one of said vacuum power devices for rotating said eccentric in a predetermined direction, a lever mounted on .said interconnecting said lever and the means for operating s'aid grappling member, and means interconnecting said lever and the means for actuating a selected one of said vacuum power devices, said lever being movable in one direction to actuate said grappling, means and being movable in another direction to actu ate a selected one of said vacuum power devices.-

5. In a straddle truck, a pair of grappling members mounted one on each side of said truck and movable inwardly into position to engage a load, power means for operating said grappling members, a load hoisting mechanism connected to said grappling members for raising or lowering a load carried thereby, power means for operating said hoisting mechanism comprising a friction cone, a friction wheel engageable by said friction cone adapted tobe driven in either of opposlte directions of rotation, means connecting said friction wheel and said load hoisting mechanism, means for moving said friction cone into engagement with said friction wheel, and means for controlling the direction of movement of said last named means for determining the direction of rotation of said wheel, a control lever mounted on said straddle truck, means interconnectin said lever and the means for operating said grappling members, and means interconnecting said lever and the means for controlling the direction of rotation of said friction wheel. I

6. In a straddle truck, a pair of grappling mem-v hers mounted one on each side of said truck and movable inwardly into position to engage a load,

means for operating said grappling members,

a load hoisting mechanism connected to said grappling members for raising and lowering a load carried thereby, power means for operating said hoisting mechanism comprising a frame,

.an eccentric journaled in said frame, a drive shaft Journaled in said eccentric, driving means moimted on said shaft, a driven shaft having driving connection with said load hoisting mechanism, means mounted on said driven shaft and engageable by said driving meansfor driving said driven shaft in either of opposite directions, and means for rotating said eccentricto cause said driving means to engage the means on the driven shaft for rotating said shaft in a predetermined direction, manually operable control means on said truck, means interconnecting said control means and the means for operating said grappling members, and means interconnecting said control means and the means for rotating said eccentric.

' .7.Inastraddietruck.apairof grapplingmembersmountedoneoneach side ofsaidtruck and movable inwardly into position to engage-a load,

means for operating said grappling'members, a load hoisting mechanism connected to said grappling members for raising and lowering a load carried thereby, power means for operating said hoisting mechanism comprising a frame, an cecentric journaled in said frame, a drive shaft journaled in said eccentric, driving means mounted onsaid shaft, a driven 'shafthaving driving connection with said load hoisting mechanism, means mounted on said driven shaft and engageable by said driving means for-driving said driven shaft in either of opposite directions, means for rotating said eccentric comprising a pair of vacuum power devices, means connecting each of said vacuum 'power devices with said eccentric, and means for actuating a selected one of said vacuum po'werdevices for rotating said eccentric 'in a predetermined direction, a control lever mounted on said truck, means interconnecting said lever and the means for operating said grappling members, and means interconnecting said control lever and the means for actuating a selected one of said vacuum power devices.

8. In a straddle truck, a pair of grappling members moimted one on each side of said truck and movable inwardly into position to eng e a load, means for operating said grappling members, a load hoisting mechanism connected tosaid grappling members for raising and lowering a load carried thereby, power means for operating said hoisting mechanism comprisinga frame, an eccentric journaled in said frame, a drive shaft joumaled in said eccentric, driving means mounted on said shaft, a driven shaft having driving connection with said load hoisting mechanism, means mounted on said driven shaft and engageable by said driving means for driving said driven shaft in either of opposite directions, means for rotating said eccentric to cause said driving means to engage the means on the driven shaft for rotating said shaft in a predetermined direction, a manually operable control member on said truck, means interconnecting said control member and the means for operating said grappling members, and means interconnecting said control member and the means for rotating said eccentric,- a brake normally engaging said driven means, and means for moving said brake out of engagement with said driven means upon rotation of said eccentric.

9. In a straddle truck. a plurality of control mechanisms for controlling operation of the load carrying apparatus, a lever mounted on said truck comprising a member :lournaled for rotation in one direction, an upstanding arm on said member, an arm pivoted intermediate its ends on said first named arm for rotation about said pivot in another direction, means conecting one end of said pivoted arm with one of said control mechanisms, and means connecting said member with another of said control mechanisms whereby movement of said arm in one direction rotates said member and actuates one control mechanism and movement of said arm in another direction actuates the other of said control mechanisms.

HENRY N. DIMICK. 

